Page 111

A Message from President Young.....3 A Message from John Francis.....4 A Message from Steven Roens.....5 Undergraduate Abstracts.....6 Research Posters on the Hill.....78 Utah Conference on Undergraduate Research.....114 Honors Program.....116 Alphabetical Index.....137

Page Metadata

RESEARCH POSTERS ON THE HILL SPRING 2007 111 An In Vitro System for the Growth and Differentiation of Normal Human Bronchial Epithelial Cells Nancy Vu and Nadeem Moghal Department of Oncological Sciences Normal function of the upper respiratory tract requires control of both differentiation and proliferation. When these conditions are not maintained properly, the result can lead to life-threatening diseases. In order to investigate these functional properties, we have successfully established an in vitro culture system for the isolation, expansion, and differentiation of normal human bronchial epithelial cell (NHBE) progenitors. The composition of the upper airways varies from species to species. Although there may be functional similarities between other species and human epithelial lung cells, it is also possible that there may be functional differences. As a result, bronchial epithelial cells harvested from human lung are used to study their properties. I^B *m^ ^B sm*. Under differentiation conditions, lung progenitors can be induced â€¢ â€¢ to differentiate into a ciliated or mucosal cell lineage in vitro. Differentiating and general expansion conditions differ in media and the presence of a collagen gel or an air-liquid interface. Cells seeded onto a 3D collagen matrix or air-liquid interface can be induced to differentiate into ciliated or mucus cells, respectively. However, it is unknown which cells in a lung population are capable of differentiating. Less than 1% of the cells in vivo are proliferating and differentiating. Determining the subpopulation responsible for this phenomenon has yet to be concluded. Based on microarray RNA data, CD44, a cell surface protein, was down regulated in differentiated cells versus non-differentiated cells. As a result, CD44 seemed to be a likely candidate marker for progenitor cells. The NHBE cell population was sorted based CD44 expression intensity. To test whether the CD44 expressors were different cell populations, a second FACS analysis was completed to validate whether intensity was maintained after proliferation. This analysis showed that intensity did not remain consistent and that both cell populations were the same. To test whether CD44 sorted cells all or partially differentiated into mucin producing cells, they were seeded onto a 3D collagen matrix and allowed to proliferate. Subsequent antibody staining revealed that the cells did not all differentiate into mucin cells. Stochastic or heritable differences explain why CD44 positive cells did not all differentiate. Small subtle changes in environment such as location and signals can cause cells to differentiate in certain cell lineages. This is an example of stochastic differences. Also, cells may not be affected by small changes, but rather whether the cell was pre-determined to become a particular cell. This is an example for heritable differences between cells. Both models have yet to be tested. This research is supported with funding from The University of Utah, Huntsman Cancer Institute.